Improvement in power-thermometers



-W. D. GRIMSHAW.

Power-Thermomter.

No. 222,897. Patented Dec. 23, 1879,

Emp..

ll L L I@ f N. PETERS, PNOTOYLIYHOGRAFHER, WASHINGTON. D C.

' -UNITED STATES PATENT OEEIoE.

WILLIAM D. GRIMSHAW, OF NEW YORK, N. Y.

IMPROVEMENT IN POWER-THERMOM ETERS.

Specification forming part of Letters Patent No. 222,897, dated December 23, 1879; application filed October 30, 1879.

To all whom 'it may concern Be it known that I, WILLIAM D. GRIM- SHAW, of the city, county, and State of New York, have invented a` new and useful Improvement in Power-Thermometers, which invention is fully set forth in the following specit cation, reference being had to the accompaters, a rack-bar projecting from the outer head of one of said chambers, a shaft provided with means for transmitting motion and carrying a pinion meshing with said rack-bar, a pointer projecting radially from said shaft, and a graduated scale arranged adjacent to said pointer.

rlhe expansion of the heads of the chambers causes the rack-bar to turn the shaft, and from said shaft motion is communicated to a damper or other movable device, while the pointer indicates the degree of heat at which this action takes place.

In the drawings, the letters A A' designate two closed vessels, which are filled with air of the same pressure as the external air, or with any other duid, and constructed with elastic heads B B. These vessels AA' are metallic, and .have circular shapes, while their heads B B' are rendered elastic by means of concentric corrugations formed therein, as shown in Figa'. Said vessels A A', moreover, are con nected together at the center by a hollow joint, a, the same being situated one above the other, and the lower vessel, A', is connected to a base, G, by means of a central hollow joint, b. y

When the temperature of the air or other fluid in which my thermometer is placed rises or falls, it follows that a like eiect is produced on the air or uid contained in the sealed vessels A A', and as the inclosed air expands or condenses it acts upon the elastic heads B B', with a tendency to cause these heads to rise and fall, which they are capable of doing by reason of their elasticity.

By the arrangement of the two vessels AA' the heads of one vessel act upon those of the other vessel and displace the latter; but I do not wish to be restricted to the use of two vessels.

For thepurpose of steadying the vessels A A' springs or cushions o are interposed between the upper vessel and a suitable part of the thermometer-frame.

The letter D designates a rockshaft, which receives motion from the heads of the vessels A A as the same rise or fall, as before stated, so that a certain amount of power may be obtained from the rock-shaft. To this end I connect the rock-shaft D with the upper head, B, of the vessel A, using a rack and pinion, d e, for this purpose.

0n the rock-shaft D may be mounted a pulley or other device, for connecting` the same with a ventilator in an apartment, or with a damper or valve upon a heating apparatus.

The letter E designates an index-hand, secured to the rock-shaft D, and F a scale adaptedto the index-hand. This scale F is secured to the thermometer-frame, and consists of a strip of sheet metal marked with suitable characters, and arranged concentric to the shaft D.

It will be readily perceived that by the index-hand and scale the temperature of a fluid, as the air in an apartment, is indicated.

I am aware that sealed vessels with elastic heads exhausted ot' air have been used for indicating atmospheric pressures, and such not being within the scope of my invention, I hereby disclaim the same. I

What I claim as new, and desire to secure by Letters Patent, is

The combination of the air-tight chambers A A', having the elastic heads and connected at the centers of their contiguous heads, the rack-bar projecting from the center of the head ot' one of the said chambers, the shaft D, provided withl a device for transmitting lnotion and carrying the pinion e, meshing with said rack-bar, the indicator E, carried by Y said shaft, and the graduated scale F, substantially as and for the purpose set forth.

In testimony that I claim the foregoing I have hereunto set my hand and seal this 28th day of October, 1879.

W. D. GRIMSHAW.

Witnesses:

FREDRIGK HAYWARD, E. F. KASTENHUBER. 

